Am 20.07.2011 10:31, schrieb cox m. (mc12v07):
Hi,
I am trying to perform a constrained linear regression in gretl for
which the beta coefficients are all non-negative and sum to unity. Is
there anyway that I can do this?
I would suggest a simple approach first, i.e. express the third
coefficient as 1-b1-b2, use NLS, and only verify afterwards whether all
coefficients are non-negative.
If you get some negative coefficients, these might be set to zero, or
you can then think about more sophisticated solutions :-)
cheers,
sven